The invention concerns fluid filtration equipment, specially designed to be attached to injecting machines for meat pieces with a substance to be injected such as brine, proteins, phosphates or other products appropriately dissolved, to help in the preservation and/or improvement of the taste and contexture of the treated meat piece.
In conventional filtration systems, a number of filters, which are normally placed in the bottom of a receptacle superposed to the main supply reservoir of the substance to be injected, are periodically replaced by clean filters while they are thoroughly cleaned and replaced again, this task being performed by the operator in charge of the machine.
In the application for a Spanish Pat. No. 532.268, owned by the applicant, a filtration system is described which includes two receptacles with a filtering bottom, arranged in and adjacent a pouring duct for substance to be re-cycled which may be manually moved at will, placing its end on the one or on the other of those receptacles and thereby allowing continuous operation since it is possible to clean one of the receptacles' filtering bottom while the other is filtering the substance to be recovered.
In any way, the need and the importance of finding a filtering system can be well understood in which the filter cleaning can be automatically performed, keeping always a portion of filtering surface under the delivery nozzle of that substance.
Although, in principle, it would seem ideal to solve this problem with rotative filters, well known and used in other industries and which often include some peripheral scraping plates and air blast cleaning, this type of filter system has been shown to be ineffective for filtering substances like the ones injected into meat pieces due to the presence of proteins and sugars in thoses substances. (These cause the surface tension of the brine or the liquid to be recovered to decrease down to values which tend to make a film all over the receptacle's internal wall, clogging the filtering mesh and rendering it useless for its specific function, and also making difficult the cleaning operation.)
In order to provide an appropriate solution to these problems, what I propose now is a filtering apparatus basically characterized by a number of equal receptacles, the bottoms of which are provided in their full areas with a filtering screen having a mesh suitable to prevent the clogging of the injecting needles.